Differential pliers.



PATENTBD JUNE 2'7, 1905.

J. L. KNIGHT.

DIFFERENTIAL PLIERS.

APPLICATION FILED NOV.9,1904.

QIJAWMQSeQs all UNTTED STATES Batentecl June 27, 1905.

ATENT FFIcE.

DIFFERENTIAL PLIERS- SPECIFICATION forming part of Letters Patent No. 793,200, dated June 27, 1905.

Application filed November 9, 1904:. Serial No. 232.047.

1' r/Z 11-70mm it rib/t1 0071,0077.-

Be it known that I, JONATHAN Lnn KNIGHT, a citizen of the United States, residing at Kansas City, in the county of Jackson and State of Missouri, have invented certain new and useful Improvements in Differential Pliers, of which the following is a Specification.

This invention relates to wire and sheetmetal working tools, and more especially to improvements in that class of tools known as differential pliers, as exemplified in my pending application, Serial No. 197,012, filed March T, 190&, my objects in this connection being to produce means for automatically opening the pliers when desired for regulating the distance which the jaws may be distended and for easily and quickly clipping or cutting sheet metal or wire.

lVith these general objects in view the invention consists in certain novel and peculiar features of construction and combinations of parts, as hereinafter described and claimed, and in order that it may be fully understood reference is to be had to the accompanying drawings, in which Figure 1 is a view, partly in side elevation and partly in section, of differential pliers embodying my improvement-s. Fig. 2 is an edge view of the same. Fig. 3 is a section on the line H1 111 of Fig. 1. Fig. 4 is an enlarged detail showing the pliers with the grippingfaces of the jaws diverging forwardly. Fig. 5 is a similar view with the gripping-faces of the jaws converging forwardly and also shows one of the handles broken away to more clearly disclose the construction and operative relation of the wire cnttingorclipping lever. Fig. 6 is a detail perspective view of the wire cutting or clipping lever.

In the said drawings, 1 designates the bandles of the pliers, said handles being preferably of metal stamped or pressed to segmental form in cross-section, with thehollow side disposed inwardly, the hollow portions of the handles flaring rearwardly, by preference, and their front portions being bifurcated, as at 2, to provide the parallel arms 3 3, one set of the arms 3 being preferably stamped outwardly, as at 1, to receive the other set, so that said arms 3 shall occupy corresponding planes.

The proximate arms of the handles cross each other and at such crossing-point are pivoted together by alined rivets 5, there being two rivets provided in order to produce an openthroat tool that is, a tool adapted to grasp an object both forward and rearward of the pivotal point.

6 and T designate jaws which project both forward and rearward of pivots 5 and through the bifurcated portions of the handles, the jaws being pivoted, as at 8, to the front ends of the arms 8 of the handles at the opposite side of the pivotal point 5, so that the approach of the handles shall result in corresponding movement of the j a-ws,and v ice versa, as in the ordinary parallel-jaw pliers. For compactness of construction the opposite sides of the rear portion of each jaw are recessed, as at 9, and projecting into said recesses contiguous to the gripping-faces of the jaws are pivots 10, carried by the handles, as shown. Outward of pivots 10 and rigidly carried by the jaws within said recesses are pivots 11, which do not extend through the handles, and mounted pivotally on pivots'lO within recesses 9 are links 12, provided in their outer ends with holes 13 of relatively much greater diameter than and engaging pivots 11.

As thus far described the tool is in principle and in fact almost a duplicate of the differential pliers of my pending application hereinbeforc referred to and to which reference is herewith made for a full understanding of the operation of the tool -that is, for a full explanation as to why the jaws automatically adapt themselves to gripping objects with parallel faces or objects, as at 14 and 15, respectively, which diverge or converge forwardly, as shown clearly in Figs. 4 and Referring now to the features of novelty of this application, 16 designates a cross-pin bridging the hollow portion of one of the bandles, and 17 a retractilc spring arranged within said handle and secured at its rear end to said pin and at its frontend to ahook 18, projecting from the contiguous end of jaw 6, the element 18 being preferably in the form of a hook in order that the spring may be easily and quickly attached to or detached from said jaw. By this arrangement it will be seen that as the handles are gripped and pressed together the jaws move inward and slightly forward, which action, in conjunction with the inward and slightly-rearward movement of pin 16, results in stretching or tensioning spring 17, so that as the pressure on the handle is removed said spring may retract, and thereby distend the jaws and handles, as will be readily understood.

For the purpose of arresting the distending movement of the jaws at any desired point an adjustable stop in the form of a screw 19 is secured in and projects rearwardly from the rear portion of jaw 7 within the hollow portion of the proximate handle and in the path of an obliquely-arranged cross-piece 20, bridging and rigidly carried by said handle. As shown in full lines, Fig. 1, the outward pressure of said cross-piece 20 against stop 19 prevents the jaws from moving a greater distance apart. If it is desired that said jaws shall move a greater distance apart, the handles are pressed together, which results, as usual, in the forward and inward movement of the jaws and the downward and rearward movement of the handles, the stop 19 partaking of the jaw movement and the cross-piece of the bandle movement. As a result the cross-piece is disposed out of alinement, and the opening 21 in said handle is brought into alinement with the stop, so that a screw-driver or equivalent tool (not shown) may be inserted through said opening for the purpose of screwing the stop farther inward into the jaw. By this arrangement it is obvious that the handles must travel a greater distance outward, and consequently move the jaws an increased distance apart before the cross-piece 20 engages the stop and limits such movement. To reduce the distention movement of the jaws, the foregoing operations are repeated, except that the stop is unscrewed, so that it shall project farther from the end of the jaw, and consequently shall be engaged more quickly by the cross-piece upon the next opening movement of the tool. The advantage of this or equivalent means for limiting the distention of the jaws is that it permits the tool to be set so that the jaws will be barely far enough apart to successfully grip articles of the same width or thickness, and thus enable the operator to manipulate the tool with greater celerity, and therefore perform his work more expeditiously than if the tool opened to its widest extent after each gripping operation.

For the purpose of clipping or cutting sheet metal or wire with the advantage of relatively enormous leverage 1 provide a flat cutting-lever, of substantially L shape, to produce a leverage-arm 22 and a cutting-arm 23, one of the jaws-6 in this instance being recessed in one side, as at 24, to receive arm 22, and the other jaw, as at 25, to receive the cutting-arm 23, said lever being fitted snugly against the clearly, so that the throat of the tool shall not I be materially contracted, and the cutting-arm of the lever operates with the usual shearing action over the transverse groove 28 in the outer edge of jaw 7 By. the arrangement described it will be seen that a compound lever age is obtained on the wire or metal being cut, the tool-handle forming the primary lever, so as to bring a relatively great pressure on the cutting or secondary lever, the latter operating on the pivot 5, so as to act in opposition to the opposite wall of the groove 28, which forms the other jaw of the cutting mechanism. In this operation it will be noted that the jaws of the cutting mechanism do not cut by simpl y a crushing pressure, as in the ordinary wire-clipper, but have a relatively shearing movement, and therefore perform their function under the application of a minimum exertion of power on the tool-handlesthat is to say, as the cutting-arm 23 moves rearward] y around pivot 5 the grooved jaw 7 instead of moving forwardly around said pivot moves approximately radially toward it, as will be apparent by reference to the full and dotted lines of Fig. 1, this action giving, in effect, a draw-cut on the wire or sheet metal operated upon.

From the above description it will be apparent thatI have produced differential pliers embodying the features of advantage enumerated as desirable in the statement of the object of the invention, and while I have illustrated and described the preferred embodiment of such features it is obvious that they are susceptible of modification in various particulars without departing from the principle and scope of the appended claims.

Having thus described the invention, what I claim as new, and desire to secure by Letters Patent, is r 1. A differential pliers, comprising crossed handles pivoted together at their crossingpoint, jaws pivoted to the front ends of the handles and projecting rearward of said pivotal point, links pivotally connecting the jaws and handles rearward of said pivotal point, and a spring tending to move the jaws and handles apart.

2. A differential pliers, comprising crossed handles pivoted together at their crossingpoint, jaws pivoted to the front ends of the handles and projecting rearward of said pivotal point, links pivotally connecting the jaws and handles rearward of said pivotal point, and a retractile spring connecting one of the jaws with the proximate handle for the purpose of automatically opening the tool.

3. A differential pliers, comprising crossed handles pivoted together at their crossingpoint, jaws pivoted to the front ends of the handles and projecting rearward of said pivotal point. links pivotally connecting the jaws and handles rearward of said pivotal point, and adjustable means for limiting the distention movement of the jaws.

e. A differential pliers, comprising crossed handles pivoted together at their crossingpoint, jaws pivoted to the front ends of the handles and projecting rearward of said pivotal point, links pivotally connecting the jaws and handles rearward of said pivotal point, a cross-piece and an adjustable stop for contact with each other to limit the distention of the jaws, one of said movement-limiting elements being carried by the jaw and the other by the proximate handle.

A dilfcrential pliers, comprising crossed handles pivoted together at their crossingpoint, jaws pivoted to the front ends of the handles and projecting rearward of said pivotal point, links pivotally connecting the jaws and handles rearward of said pivotal point, a eross-piece carried by one of the handles, and a threaded pin mounted in the contiguous end of the proximate jaw and adapted for engagement by said cross-piece.

6. A ditl'erential pliers, comprising crossed handles pivoted together at their crossingpoiut, jaws pivoted to the front ends of the handles and projecting rearward of said pivotal point and one of them provided with a cutting-jaw, links pivotally connecting the first-named jaws and handles rearward of said pivotal point. an angle-lever pivoted on the pivot of the handles and having its cuttingarm fitting flatly against one of the plierjaws, and its other arm fitting flatly against the other plier-jaw. and pivotally connected thereto and to the connecting-handle.

7. A differential pliers, comprising crossed handles pivoted together at their crossingpoint, jaws extending forwardly and rearwardly of such pivotal point and pivoted to the front ends of the handles, and means for connecting the rear portions of each jaw with the handle pivotally carrying the companion jaw and having differential or lost motion with respect to the jaws; and a lever pivoted coincidently with the pivot of said handles and having an arm pivoted to the front end of one handle and a cutting-arm bearing flatly against the jaw at the opposite side of the handle-pivot from the first-named arm.

In testimony whereof I aflix my signature in the presence of two witnesses.

JONATHAN LEE KNIGHT.

Witnesses:

H. C. Rononns, Gr. 1'. 'luonrn. 

